v0.1.0-alpha: interactive demo platform core

- Fastify API: demos/steps CRUD, content-addressed assets, scoped API keys
  (read/author/publish/admin, draft-only default per D4)
- Player: image + sandboxed DOM steps, hotspots, tooltips, keyboard nav,
  privacy-first beacons (no IP storage, viewer tokens only — R7)
- Editor: React SPA — demo list, drag-to-draw hotspots, annotations, publish
- MCP server: Streamable HTTP, scope-filtered tools, untrusted-data wrapping
  on viewer-supplied content (R8); platform never calls a model
- Capture extension (MV3): screenshot-flow recording, hotspots pre-placed
  from real clicks
- Docker: single app image + postgres, Traefik-ready (expose only)

E2E verified: capture->author->publish->play->beacon->lead->analytics + full
MCP tool surface with scope filtering.

extension/manifest.json

@@ -0,0 +1,11 @@
+{
+  "manifest_version": 3,
+  "name": "Demo Platform Capture",
+  "version": "0.1.0",
+  "description": "Capture click-through product demos. Screenshot mode (v0); DOM mode coming in v1.",
+  "permissions": ["activeTab", "tabs", "storage", "scripting"],
+  "host_permissions": ["<all_urls>"],
+  "action": { "default_popup": "popup.html", "default_title": "Demo Capture" },
+  "background": { "service_worker": "background.js" },
+  "icons": {}
+}